Psocess for the preparation of



United States Patent 3,109,863 PRGCESE? FOR THE PREPARATION OFCYCLQHEXYLETHYL ALCOHGL Gilbert Bo and Philippe Perras, Lyon, France,assignors to Societe des Usines Chimi ues Rhone-Paulette, laris, rance,a French body corporate No Drawing. Filed lllay 23, 1960, Ser. No.31,220 Claims priority, application France May 29, 1959 2 Claims. (Cl.260-617) This invention relates to a new process for the preparation ofcyclohexylethyl alcohol, which product and its esters are employed inperfumes.

It is known to prepare cyclohexylethyl alcohol by catalytichydrogenation of phenylethyl alcohol which, in turn, can be obtained bycatalytic hydrogenation of l,2epox phenylethane.

It follows that it would be advantageous to devise a method wherebycyclohexyiethyl alcohol could be obtained in one operation, that is by asingle hydrogenation of 1,2-epoxyphenylethane. In the first phase, i.e.the reduction of an epoxy group to an hydroxy group, good yields areobtained by operating, for example, with Raney nickel at lowtemperatures. The second phase, i.e. hydrogenation of the aromaticnucleus, requires more vigorous operating conditions. Hydrogenation with6% by weight of Raney nickel at 200 C. under 210 atmospheres pressurehas previously been described and under these conditions the yield ofcyclohexylethyl alcohol is only 53%. A quantitive yield has beenobtained, however, by operating at low temperatures, i.e. -30 C., but inorder to obtain this result it has been necessary to employ 150% byweight of Ran y nickel and a reaction period of 96 hours, which condions render the industrial application of this process impracticable. Inview of the present state of knowledge in the art, therefore, therewould seem a priori to be very little chance of exceeding a yield of 50%in an industrial process for the production of cyclohexylethyl alcoholby combining the aforesaid two hydrogenation phases. Moreover, it hasbeen observed that if 1,2- epoxyphenylethane is hydrogenated at 130140C. and under pressure in the presence of Raney nickel, two sidereactions take place: polymerisation of the 1,2-epoxyphenylethane, andformation of ethylcyclohexane, both of which lower the yield ofcyclohexylethyl alcohol.

According to the present invention there is provided a process for theproduction of cyclohexylethyl alcohol in excellent yields, whichcomprises introducing gradually 1,2-epoxyphenylethane into a suspensionof a hydrogenation catalyst in an inert liquid medium at a temperaturefrom 100 to 200 C. and under 50 to 300 atmospheres of hydrogen.

In order to obtain the higher yields in the foregoing process, it isdesirable that the speed of introduction of the epoxyphenylethane shouldbe controlled so that its proportion in the reaction vessel remains aslow as possi- -le throughout the hydrogenation, thus avoiding as far aspossible the formation of by-products.

Suitable catalysts are those capable of facilitating the hydrogenationof the aromatic nucleus, for example, Raney nickel, Raney cobalt andsupported ruthenium. The inert liquid medium should be a liquid inert tothe conditions of the reaction, for example, methanol, ethanol or thehydrogenation product itself, i.e. cyclohexylethyl alcohol. The quantityof catalyst which should be employed depends upon its activity. Thus,supported ruthenium (e.g. on calcium carbonate or alumina) canefl'ecddddfifiB Patented Nov. 5, i903 tively be employed in a proportionas small as 0.1% by weight of ruthenium calculated on the total quantityof 1,2-epoxyphenylethane introduced. In the case of Raney nickel, aquantity corresponding to 1% by weight may be employed, but it ispreferable to use 540%. After the reaction, the nickel can be recoveredand used again for a subsequent hydrogenation, if desired after theaddition of a small quantity of fresh catalyst. The nickel may bealloyed with small quantities of activator metals, such as iron orchromium.

The preferred hydrogenation temperatures range from 13 0 to 150 C. andthe preferred pressures range from to 120 atmospheres.

The following example will serve to illustrate the invention.

Example Into a 3.6 litre autoclave provided with a rotating-frameagitator are introduced 100 g. of Raney nickel in suspension in 200 ml.of ethanol. The air in the autoclave is replaced by nitrogen, and thenby hydrogen, after which at 140 C. by slight heating.

1000 g. of the epoxyphenylethane is injected during 3 hours and thepressure drops from 100 to 80 atmospheres and is restored to 100atmospheres 15 times. The hydrogenation is continued for a further 3hours 40 minutes at 140 C. until the absorption of hydrogen ceases, butduring this latter period the pressure drops from 100 to 80 atmospheresand is restored only 3 times and on the fourth drop settles atatmospheres.

After cooling and filtering oil the catalyst, the following areseparated by distillation: 125 g. of ethylcyclohexane; 806 g. ofcyclohexylethyl alcohol, boiling at 106 C. at 19 mm. Hg; and 20 g. ofresidues (consisting mainly of polymers of epoxyphenylethane). The yieldof cyclohexylethyl alcohol is 75.5% based on the weight of theepoxyphenylethane.

If, instead of the epoxyphenylethane being progressively introduced overa period of 3 hours, the same quantity is introduced all at once, then,after hydrogenating for 8 hours 30 minutes (all other conditions beingthe same) the following are separated by distillation: 372 g. ofethylcyclohexane; 484 g. of cyclohexylethyl alcohol; and 67 g. ofresidues. The yield of cyclohexylethyl alcohol in this instance istherefore only 45% based on the weight of the epoxyphenylethane.

We claim:

1. A process for the production of cyclohexylethyl alcohol whichcomprises gradually introducing 1,2-epoxyphenylethane into a suspensionof a hydrogenation catalyst selected from the class consisting of Raneynickel, Raney cobalt and supported ruthenium in an inert liquid mediumselected from the class consisting of methanol, ethanol andcyclohexylethyl alcohol, at a temperature from to 200 C. and under 50 to300 atmospheres of hydrogen, the rate of addition of the1,2-epoxyphenylethane being such that the proportion thereof in thesuspension is maintained as low as possible throughout he hydrogenation.

2. A process according to claim 1 wherein the hydro- 3 genation iseffected at a temgerature from 130 to 150 C. OTHER REFERENCES and under80 to 120 atmosPneres of hydrogen- Newman et 211.: Jour. Amer. Chem.800., 71:3362- References Cited in the file of this patent 63 2 P g 222Offi'fifi yn Pines et a1.: Jour. Chem. 800., vol. 77 (1955), pp.

UNITED STATE? PATENTS 5 5099 to 5102 4 pages). (Copy in ScientificLibrary.)

2,555,912 Arnold June 5, 1951

1. A PROCESS FOR THE PRODUCTION OF CYCLOHEXLETHYL ALCOHOL WHICHCOMPRISES GRADUALLY INTRODUCING 1,2-EPOXYPHENYLETHANE INTO A SUSPENSIONOF A HYDROGENATION CATALYST SELECTED FROM THE CLASS CONSISTING OF RANEYNICKEL, RANEY COBALT AND SUPPORTED RUTHENIUM IN AN INERT LIQUID MEDIUMSELECTED FROM THE CLASS CONSISTING OF METHANOL, ETHANOL ANDCYCLOHEXYLETHYL ALCOHOL, AT A TEMPERATURE FROM 100* TO 200*C. AND UNDER50 TO 300 ATMOSPHERES OF HYDROGEN, THE RATE OF ADDITION OF THE1,2-EPOXYPHENYLETHANE BEING SUCH THAT THE PROPORTION THEREOF IN THESUSPENSION IS MAINTAINED AS LOW AS POSSIBLE THROUGHOUT THEHYDROGENATION.